A variety of industrial presses are known in the art. One such press is the press brake. Press brakes are commonly used to bend or otherwise deform sheet-like workpieces, such as sheet metal workpieces. A conventional press brake has an upper beam and a lower beam, at least one of which is movable toward and away from the other. Typically, the upper beam is movable vertically while the lower beam is fixed in a stationary position. It is common for tooling (e.g., a male forming punch and a female forming die) to be separately mounted on the press brake upper and lower beams. For example, in some cases, the punch is to be mounted on the press upper beam, while the female forming die is to be mounted on the press lower beam.
Typically, the punch has a workpiece-deforming surface (or “tip”). To that end, if the punch is mounted on an upper beam of a press brake, its tip is generally oriented downward. The configuration of the tip is dictated by the shape to which one desires to deform a workpiece. In contrast, the die typically has a recess, bounded by one or more workpiece-deforming surfaces, that is aligned with the punch tip. In cases where the punch is mounted on the press brake upper beam, the die in turn is mounted on the lower beam of a press brake, with its recess generally oriented upward. The configuration of the recess corresponds to the configuration of the punch's tip. Thus, when the beams are brought together, a workpiece positioned between them is pressed by the punch into the die to give the workpiece a desired deformation (e.g., a desired bend).
In order to accurately deform a workpiece, it is necessary for the tooling (e.g., punch and die) to be securely mounted to the press. As described above, for a press brake, this generally involves mounting a select punch and a select die on opposing beams of the press brake. In so doing, the punch and die are generally mounted by forcibly clamping each with corresponding holders of such beams. To that end, each punch generally has a first end region adapted to be clamped by the holder, and a second end that forms the tip or working (e.g., bending/deforming) portion thereof. Likewise, each die generally has a first region adapted to be clamped by the holder, and a second region that forms the recess or working portion thereof.
Press tooling designs continue to evolve. For example, some punches and dies have been designed to include separable portions, thereby involving assemblies (i.e., tooling assemblies) instead of single integral bodies. Regarding punch assemblies, the separable portions generally involve a punch tip holder and a punch tip, with these portions configured to be coupled or decoupled as desired. Likewise, die assemblies involve separable die body and die insert portions that can be similarly coupled and decoupled. Such punch and die assembly designs are advantageous, as they enable the punch tips and die inserts to be removed and replaced or sharpened after they wear down. Unfortunately, these designs also tend to have aspects that are less than ideal.
For example, the methods employed in coupling/decoupling the punch tip to/from the corresponding tip holder can be demanding. In particular, the punch tip is often coupled to the tip holder by aligning openings provided along longitudinal extents of their bodies, and then securing fasteners in the aligned openings. However, properly aligning the punch tip and tip holder for coupling there between can be a laborious process, particularly given the sizes and/or weights of conventional punches. Additionally, in many cases, the coupling process requires performing a reference stroke to seat the tip against the holder prior to operatively coupling the tip and holder together. Further, having to tighten/loosen fasteners in the process can be time consuming, difficult to do, or both.
With further reference to the above-described punch assemblies, they have also been found to exhibit reduced integrity and show increased wear over time, as compared to their single integral-body counterparts. For example, when used in pressing operations, a conventional punch assembly formed by conjoining separate holder and tip portions exhibits a diminished structural integrity as compared to an integral-body punch. In addition, pressing operations tend to exert greater stresses on adjoining surfaces of the conjoined portions, thereby causing increased wear in these areas over time.
Further, in some cases, punch assemblies have been found deficient in uniformly distributing pressing force. For example, in some designs, the holder interfaces with the tip at an angle, causing some areas of the holder to encounter greater pressing force than others. This can lead to less than optimum force distribution and transfer to the tip during a deforming/bending process, and the efficiency of the process may consequently be reduced. In addition, increased wear can be found in the areas encountering the greater forces, which impart greater stresses. The above issues often are aggravated when using larger tip sizes.
It should be appreciated that many of the above-described aspects are found to exist with conventional die assemblies as well.